1. Technical Field
The present invention relates to a packaging machine for forming a bag and using the bag to package an article, as well as a suction control apparatus included in a packaging machine.
2. Related Art
Packaging machines have been known in the art (see Japanese Laid-Open Patent Application No. 2002-166904 and Japanese Laid-Open Patent Application No. 2004-155465, for example).
Japanese Laid-Open Patent Application No. 2002-166904 discloses a filling and packaging machine. The filling and packaging machine forms a continuous packaging bag by longitudinally and laterally sealing a film using longitudinal and lateral sealing mechanisms, the film being fed out from a film roller; and the filling and packaging machine fills the interior of the continuous packaging bag P with a filler substance. The filling and packaging machine comprises a sealing plate, temperature detection means, temperature adjustment means, and control means. The sealing plate is set up on a pair of heat seal rolls to which the longitudinal and lateral sealing mechanisms are provided. The sealing plate is heated by an electric heater. The temperature detection means detects the temperature of the sealing plate. Temperature adjustment means adjusts the temperature of the sealing plate on the basis of temperature information detected by the temperature detection means. The control means has a power-saving mode. The power-saving mode makes it possible to set a proper temperature in the temperature adjustment means K4, and controls the temperature adjustment means so as to cease heating of the sealing plate or set temperature lower than the proper temperature.
The packaging machine of Japanese Laid-Open Patent Application No. 2004-155465 comprises a pair of front and rear sealing jaws and a pair of rotation shafts. The packaging machine also comprises a first servo motor for driving the sealing jaws around the rotation shafts and a second servo motor for driving the rotation shafts so as to bring them closer together or move them apart from each other in a horizontal direction. The packaging machine causes the first servo motor and the second servo motor to function in tandem, and moves the sealing jaws so as to describe a D-shaped trajectory. The packaging machine ceases the supply of power to respective heaters of the longitudinal sealing mechanism and the lateral sealing mechanism while the power supply to the servo motors is on. On the other hand, while the power supply to the servo motors is off, the power supply to the heaters is permitted and the power supply periods of the heaters are controlled so as not to overlap each other.